The present application relates generally to a weather radar system. More particularly, the present application relates to an airborne radar or other airborne sensor system which is capable of detecting obstacles on a runway when an aircraft is in a take-off mode, a landing mode, or a taxi mode and which is capable of detecting a weather phenomenon.
Incursion systems, such as runway incursion systems, are utilized to determine if an obstacle is in the path of an aircraft or other vehicle. Conventional runway incursion systems are generally one of two types. The first type utilizes signals cooperatively provided from the obstacle on the runway; the second type utilizes radar or other electromagnetic energy signals to actively sense the presence of an obstacle on the runway without the obstacles active cooperation.
U.S. Pat. No. 6,850,185, entitled, “Runway Obstacle Detection System and Method” invented by Woodell and assigned to the Assignee of the present application describes an example of the second-type of conventional runway incursion system. U.S. Pat. No. 6,850,185 describes a weather radar system that utilizes active sensing of obstacles by transmitting electromagnetic beams and receiving the beam that bounces off obstacles in the path of the aircraft. The weather radar system is also capable of detecting weather phenomena. U.S. application Ser. No. 10/941,616 filed by Woodell et al. on Sep. 15, 2004 and assigned to the Assignee of the present application also discloses a weather radar system capable of detecting obstacles on a runway as well as weather phenomena. U.S. Pat. No. 6,850,185 and U.S. patent application Ser. No. 10/941,616 are incorporated herein by reference. U.S. patent application Ser. No. 11/486,774 entitled, “Combined Runway Obstacle Detection System and Method,” filed Jul. 14, 2006 by Woodell et al., incorporated herein by reference and assigned to the Assignee of the present application discloses a runway incursion system using principles of the first and second type.
Conventional aircraft weather radar systems are capable of scanning for certain weather phenomena, such as windshear, turbulence or micro-burst situations. U.S. Pat. No. 6,388,608 assigned to the Assignee of the present application and incorporated herein by reference discloses a weather radar system with windshear detection capabilities. U.S. Pat. No. 6,388,608 discloses an embodiment that detects turbulence or windshear by scanning at two or more tilt angles and determining wind speeds at various elevations. A gradient of average wind speed is determined and compared to predetermined known gradients. When a match is made, the known vertical shear components are removed and the resulting data is used to detect turbulence.
Detecting windshear, turbulence and/or micro-burst situations requires that the weather radar scan the area and process weather radar returns to determine if the windshear, turbulence or micro-burst situation is present. Windshear, turbulence or micro-burst warnings are generally very desirous when the airplane is in the landing, taxi and take-off modes. However, scanning for weather phenomenon, such as, windshear, turbulence and/or micro-bursts and the subsequent analysis for the phenomenon generally requires a significant amount of scanning time, processing time, and processing power.
Detecting runway incursions generally also requires a significant amount of scanning time, processing time, and processing power. Like detecting certain weather phenomenon, detecting runway incursions is desirous during the landing, take-off, and taxi modes. Accordingly, weather radar systems have a limited amount of time to sample the weather environment to support weather phenomenon warning functions and to sample the runway and taxiway to support runway incursion warning functions.
Accordingly, there is a need for a scanning strategy that reduces the amount of time required to detect weather phenomena, such as windshear (e.g. microbursts) and/or turbulence, and runway incursion. There is also a need for a radar system that removes redundant functions associated with weather detection and runway or taxiway obstacle detection. Further, there is a need for a cost effective system for and method of runway obstacle detection and weather detection. Yet further there is a need for an efficient process of detecting runway and taxiway incursions and weather phenomena that is important to take-off, taxi, and landing modes.